1. Field
The invention is in the field of air filtration systems, particularly personal air filtration systems which filter air and supply such filtered air to one, or several, individuals or to an area occupied by one, or several, individuals. It is also in the field of supplying filtered air to an individual or area occupied by an individual.
2. State of the Art
Air pollution, whether pollution of outdoor atmospheric air naturally with dust, pollens, or other natural pollutants or with pollutants introduced by man or machines, or indoor pollution such as dust, germs, bacteria, etc. which enter the air inside a room or other closed area and may be distributed throughout the room or area, or throughout a whole building by the building heating or air conditioning system, is a major problem with significant health risks. While environmental concerns dictate reduction of some of the source of man-made pollution, serious pollution remains.
Various types of air filtering units designed to remove various types of pollutants have been suggested. Room air filter units, such as shown in U.S. Pat. No. 5,453,049, draw in room air, filter it, and then discharge the filtered air back into the room. However, while some benefit may be obtained with such units as pollutants in the room may be reduced, the air in the room remains polluted and persons in the room are breathing the mixed, polluted air.
Systems have also been suggested, such as by U.S. Pat. No. 4,872,397, for providing a personal indoor environment in a person's individual work area. In addition to individually controlled heating and cooling, the air entering such area may also be filtered. Again, however, this air is generally mixed with ambient air around the work area so the air in the work area is actually a mixture of filtered and polluted ambient air.
Large filtering units may be used to provide a clean environment in "clean rooms". However, the use of "clean rooms" is generally required for particular manufacturing processes, such as in semiconductor manufacturing, and is not provided for the benefit of occupants of the rooms. Thus, clean rooms are provided only when necessary for particular manufacturing processes and are not generally provided to keep people from polluted air.
Various personal air filtration devices have been disclosed. U.S. Pat. No. 5,667,564 shows a small device which filters and ionizes air which flows from one end of the device. Presumably, the device is worn by a user who directs the purified air toward the user's face. U.S. Pat. Nos. 5,054,479 and 5,054,480 each disclose headgear having a face covering shield and the supplying of filtered air to the area between the face and shield so that the user is supplied with filtered air for breathing. However, such devices require wearing of the face shield in order to get the purified air.